diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 3f28909..9772932 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -110,4 +110,5 @@ mod p42_trapping_rain_water;
 mod p58_length_of_last_word;
 mod p151_reverse_words_in_a_string;
 mod p28_find_the_index_of_the_first_occurrence_in_a_string;
-mod p68_text_justification;
\ No newline at end of file
+mod p68_text_justification;
+mod p125_valid_palindrome;
\ No newline at end of file
diff --git a/src/problem/p125_valid_palindrome.rs b/src/problem/p125_valid_palindrome.rs
new file mode 100644
index 0000000..9994b55
--- /dev/null
+++ b/src/problem/p125_valid_palindrome.rs
@@ -0,0 +1,51 @@
+/**
+ * [125] Valid Palindrome
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn is_palindrome(s: String) -> bool {
+        let s = s.to_lowercase();
+        let mut result = Vec::new();
+
+        for c in s.chars() {
+            if c.is_ascii_alphabetic() || c.is_digit(10) {
+                result.push(c);
+            }
+        }
+
+        if result.len() <= 1 {
+            return true;
+        }
+
+        let mut i = 0;
+        let mut j = result.len() - 1;
+
+        while i < j {
+            if result[i] != result[j] {
+                return false;
+            }
+
+            i += 1;
+            j -= 1;
+        }
+        
+        true
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_125() {
+        assert!(Solution::is_palindrome("A man, a plan, a canal: Panama".to_owned()));
+        assert!(!Solution::is_palindrome("0P".to_owned()));
+    }
+}